agetty.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

/* agetty.c - another getty program for Linux. By W. Z. Venema 1989
   Ported to Linux by Peter Orbaek <[e-mail]>
   This program is freely distributable. The entire man-page used to
   be here. Now read the real man-page agetty.8 instead.

   -f option added by Eric Rasmussen <[e-mail]> - 12/28/95
   
   1999-02-22 Arkadiusz Mi秌iewicz <[e-mail]>
   - added Native Language Support

   1999-05-05 Thorsten Kranzkowski <[e-mail]>
   - enable hardware flow control before displaying /etc/issue
   
*/

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <termio.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <ctype.h>
#include <utmp.h>
#include <getopt.h>
#include <time.h>
#include <sys/file.h>
#include "xstrncpy.h"
#include "nls.h"

#ifdef __linux__
#include "pathnames.h"
#include <sys/param.h>
#define USE_SYSLOG
#endif

 /* If USE_SYSLOG is undefined all diagnostics go directly to /dev/console. */

#ifdef	USE_SYSLOG
#include <syslog.h>
#endif

 /*
  * Some heuristics to find out what environment we are in: if it is not
  * System V, assume it is SunOS 4.
  */

#ifdef LOGIN_PROCESS			/* defined in System V utmp.h */
#define	SYSV_STYLE			/* select System V style getty */
#endif

 /*
  * Things you may want to modify.
  * 
  * If ISSUE is not defined, agetty will never display the contents of the
  * /etc/issue file. You will not want to spit out large "issue" files at the
  * wrong baud rate. Relevant for System V only.
  * 
  * You may disagree with the default line-editing etc. characters defined
  * below. Note, however, that DEL cannot be used for interrupt generation
  * and for line editing at the same time.
  */

#ifdef	SYSV_STYLE
#define	ISSUE "/etc/issue"		/* displayed before the login prompt */
#include <sys/utsname.h>
#include <time.h>
#endif

#define LOGIN " login: "		/* login prompt */

/* Some shorthands for control characters. */

#define CTL(x)		(x ^ 0100)	/* Assumes ASCII dialect */
#define	CR		CTL('M')	/* carriage return */
#define	NL		CTL('J')	/* line feed */
#define	BS		CTL('H')	/* back space */
#define	DEL		CTL('?')	/* delete */

/* Defaults for line-editing etc. characters; you may want to change this. */

#define DEF_ERASE	DEL		/* default erase character */
#define DEF_INTR	CTL('C')	/* default interrupt character */
#define DEF_QUIT	CTL('\\')	/* default quit char */
#define DEF_KILL	CTL('U')	/* default kill char */
#define DEF_EOF		CTL('D')	/* default EOF char */
#define DEF_EOL		0
#define DEF_SWITCH	0		/* default switch char */

 /*
  * SunOS 4.1.1 termio is broken. We must use the termios stuff instead,
  * because the termio -> termios translation does not clear the termios
  * CIBAUD bits. Therefore, the tty driver would sometimes report that input
  * baud rate != output baud rate. I did not notice that problem with SunOS
  * 4.1. We will use termios where available, and termio otherwise.
  */

/* linux 0.12 termio is broken too, if we use it c_cc[VERASE] isn't set
   properly, but all is well if we use termios?! */

#ifdef	TCGETS
#undef	TCGETA
#undef	TCSETA
#undef	TCSETAW
#define	termio	termios
#define	TCGETA	TCGETS
#define	TCSETA	TCSETS
#define	TCSETAW	TCSETSW
#endif

 /*
  * This program tries to not use the standard-i/o library.  This keeps the
  * executable small on systems that do not have shared libraries (System V
  * Release <3).
  */
#ifndef BUFSIZ
#define	BUFSIZ		1024
#endif

 /*
  * When multiple baud rates are specified on the command line, the first one
  * we will try is the first one specified.
  */

#define	FIRST_SPEED	0

/* Storage for command-line options. */

#define	MAX_SPEED	10		/* max. nr. of baud rates */

struct options {
    int     flags;			/* toggle switches, see below */
    int     timeout;			/* time-out period */
    char   *login;			/* login program */
    char   *tty;			/* name of tty */
    char   *initstring;			/* modem init string */
    char   *issue;			/* alternative issue file */
    int     numspeed;			/* number of baud rates to try */
    int     speeds[MAX_SPEED];		/* baud rates to be tried */
};

#define	F_PARSE		(1<<0)		/* process modem status messages */
#define	F_ISSUE		(1<<1)		/* display /etc/issue */
#define	F_RTSCTS	(1<<2)		/* enable RTS/CTS flow control */
#define F_LOCAL		(1<<3)		/* force local */
#define F_INITSTRING    (1<<4)		/* initstring is set */
#define F_WAITCRLF	(1<<5)		/* wait for CR or LF */
#define F_CUSTISSUE	(1<<6)		/* give alternative issue file */
#define F_NOPROMPT	(1<<7)		/* don't ask for login name! */

/* Storage for things detected while the login name was read. */

struct chardata {
    int     erase;			/* erase character */
    int     kill;			/* kill character */
    int     eol;			/* end-of-line character */
    int     parity;			/* what parity did we see */
    int     capslock;			/* upper case without lower case */
};

/* Initial values for the above. */

struct chardata init_chardata = {
    DEF_ERASE,				/* default erase character */
    DEF_KILL,				/* default kill character */
    13,					/* default eol char */
    0,					/* space parity */
    0,					/* no capslock */
};

struct Speedtab {
    long    speed;
    int     code;
};

static struct Speedtab speedtab[] = {
    { 50, B50 },
    { 75, B75 },
    { 110, B110 },
    { 134, B134 },
    { 150, B150 },
    { 200, B200 },
    { 300, B300 },
    { 600, B600 },
    { 1200, B1200 },
    { 1800, B1800 },
    { 2400, B2400 },
    { 4800, B4800 },
    { 9600, B9600 },
#ifdef	B19200
    { 19200, B19200 },
#endif
#ifdef	B38400
    { 38400, B38400 },
#endif
#ifdef	EXTA
    { 19200, EXTA },
#endif
#ifdef	EXTB
    { 38400, EXTB },
#endif
#ifdef B57600
    { 57600, B57600 },
#endif
#ifdef B115200
    { 115200, B115200 },
#endif
#ifdef B230400
    { 230400, B230400 },
#endif
    { 0, 0 },
};

#define P_(s) s
int main P_((int argc, char **argv));
void parse_args P_((int argc, char **argv, struct options *op));
void parse_speeds P_((struct options *op, char *arg));
void update_utmp P_((char *line));
void open_tty P_((char *tty, struct termio *tp, int local));
void termio_init P_((struct termio *tp, int speed, struct options *op));
void auto_baud P_((struct termio *tp));
void do_prompt P_((struct options *op, struct termio *tp));
void next_speed P_((struct termio *tp, struct options *op));
char *get_logname P_((struct options *op, struct chardata *cp, struct termio *tp));
void termio_final P_((struct options *op, struct termio *tp, struct chardata *cp));
int caps_lock P_((char *s));
int bcode P_((char *s));
void usage P_((void));
void error P_((const char *, ...));
#undef P_

/* The following is used for understandable diagnostics. */

char *progname;

/* Fake hostname for ut_host specified on command line. */
char *fakehost = NULL;

/* ... */
#ifdef DEBUGGING
#define debug(s) fprintf(dbf,s); fflush(dbf)
FILE *dbf;
#else
#define debug(s) /* nothing */
#endif

int
main(argc, argv)
     int     argc;
     char  **argv;
{
    char   *logname = NULL;		/* login name, given to /bin/login */
    struct chardata chardata;		/* set by get_logname() */
    struct termio termio;		/* terminal mode bits */
    static struct options options = {
	F_ISSUE,			/* show /etc/issue (SYSV_STYLE) */
	0,				/* no timeout */
	_PATH_LOGIN,			/* default login program */
	"tty1",				/* default tty line */
	"",				/* modem init string */
	ISSUE,				/* default issue file */
	0,				/* no baud rates known yet */
    };

       setlocale(LC_ALL, "");
       bindtextdomain(PACKAGE, LOCALEDIR);
       textdomain(PACKAGE);
    
    /* The BSD-style init command passes us a useless process name. */

#ifdef	SYSV_STYLE
       {
	       char *ptr;
	       progname = argv[0];
	       if ((ptr = strrchr(argv[0], '/')))
		       progname = ++ptr;
       }
#else
       progname = "agetty";
#endif

#ifdef DEBUGGING
	dbf = fopen("/dev/ttyp0", "w");

	{	int i;
	
		for(i = 1; i < argc; i++) {
			debug(argv[i]);
		}
	}
#endif

    /* Parse command-line arguments. */

    parse_args(argc, argv, &options);

#ifdef __linux__
	setsid();
#endif
	
    /* Update the utmp file. */

#ifdef	SYSV_STYLE
    update_utmp(options.tty);
#endif

    debug(_("calling open_tty\n"));
    /* Open the tty as standard { input, output, error }. */
    open_tty(options.tty, &termio, options.flags & F_LOCAL);

#ifdef __linux__
	{
		int iv;
		
		iv = getpid();
		(void) ioctl(0, TIOCSPGRP, &iv);
	}
#endif
    /* Initialize the termio settings (raw mode, eight-bit, blocking i/o). */
    debug(_("calling termio_init\n"));
    termio_init(&termio, options.speeds[FIRST_SPEED], &options);

    /* write the modem init string and DON'T flush the buffers */
    if (options.flags & F_INITSTRING) {
	debug(_("writing init string\n"));
	write(1, options.initstring, strlen(options.initstring));
    }

    if (!(options.flags & F_LOCAL)) {
	/* go to blocking write mode unless -L is specified */
	fcntl(1, F_SETFL, fcntl(1, F_GETFL, 0) & ~O_NONBLOCK);
    }

    /* Optionally detect the baud rate from the modem status message. */
    debug(_("before autobaud\n"));
    if (options.flags & F_PARSE)
	auto_baud(&termio);

    /* Set the optional timer. */
    if (options.timeout)
	(void) alarm((unsigned) options.timeout);

    /* optionally wait for CR or LF before writing /etc/issue */
    if (options.flags & F_WAITCRLF) {
	char ch;

	debug(_("waiting for cr-lf\n"));
	while(read(0, &ch, 1) == 1) {
	    ch &= 0x7f;   /* strip "parity bit" */
#ifdef DEBUGGING
	    fprintf(dbf, _("read %c\n"), ch);
#endif
	    if (ch == '\n' || ch == '\r') break;
	}
    }

    chardata = init_chardata;
    if (!(options.flags & F_NOPROMPT)) {
	/* Read the login name. */
	debug(_("reading login name\n"));
	while ((logname = get_logname(&options, &chardata, &termio)) == 0)
	  next_speed(&termio, &options);
    }

    /* Disable timer. */

    if (options.timeout)
	(void) alarm(0);

    /* Finalize the termio settings. */

    termio_final(&options, &termio, &chardata);

    /* Now the newline character should be properly written. */

    (void) write(1, "\n", 1);

    /* Let the login program take care of password validation. */

    (void) execl(options.login, options.login, "--", logname, (char *) 0);
    error(_("%s: can't exec %s: %m"), options.tty, options.login);
    exit(0);  /* quiet GCC */
}

/* parse-args - parse command-line arguments */

void
parse_args(argc, argv, op)
     int     argc;
     char  **argv;
     struct options *op;
{
    extern char *optarg;		/* getopt */
    extern int optind;			/* getopt */
    int     c;

    while (isascii(c = getopt(argc, argv, "I:LH:f:hil:mt:wn"))) {
	switch (c) {
	case 'I':
	    if (!(op->initstring = malloc(strlen(optarg)))) {
		error(_("can't malloc initstring"));
		break;
	    }
	    {
		char ch, *p, *q;
		int i;

		/* copy optarg into op->initstring decoding \ddd
		   octal codes into chars */
		q = op->initstring;
		p = optarg;
		while (*p) {
		    if (*p == '\\') {		/* know \\ means \ */
			p++;
			if (*p == '\\') {
			    ch = '\\';
			    p++;
			} else {		/* handle \000 - \177 */
			    ch = 0;